CO2 absorption by aqueous NH3 solutions:: speciation of ammonium carbamate, bicarbonate and carbonate by a 13C NMR
CO2 absorption by aqueous NH3 solutions:: speciation of ammonium carbamate, bicarbonate and carbonate by a 13C NMR
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DOI：
10.1039/b602051h
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发表时间：
2006-01-01
期刊：
影响因子：
9.8
通讯作者：
Stoppioni, Piero
中科院分区：
文献类型：
--
作者：
Mani, Fabrizio;Peruzzini, Maurizio;Stoppioni, Piero
在常温常压条件下，NH3水溶液对CO2的吸附效率高，吸附量大，生成碳酸氢盐（HCO3-）、碳酸盐（CO32-）和氨基甲酸盐（NH2CO2-）阴离子。室温下的C-13核磁共振光谱已被证明是研究这三种离子在溶液中形态形成的一种简单可靠的方法。HCO3-/CO32-阴离子的快速平衡产生单个核磁共振峰，其化学位移取决于两种物质的相对浓度。已经开发出一种方法，将碳共振的化学位移与两种阴离子的比值联系起来。氨基甲酸酯碳峰的整合提供了该物种相对于HCO3-/CO32-对的相对量。在我们的实验条件下，在溶液中没有检测到其他物质，也没有分离出固体化合物。最后，溶液中HCO3-、CO32-和NH2CO2-的相对含量与溶液中游离氨与吸收CO2的摩尔比有关。
The absorption of CO2 in aqueous NH3 solutions occurs with high efficiency and loading capacity at room temperature and atmospheric pressure producing the ammonium salts of bicarbonate (HCO3-), carbonate (CO32-), and carbamate (NH2CO2-) anions. C-13 NMR spectroscopy at room temperature has been proven to be a simple and reliable method to investigate the speciation in solution of these three ionic species. Fast equilibration of HCO3-/CO32- anions results in a single NMR peak whose chemical shift depends on the relative concentration of the two species. A method has been developed to correlate the chemical shift of this carbon resonance to the ratio of the two anionic species. Integration of the carbamate carbon peak provided the relative amount of this species with respect to HCO3-/CO32- pair. No other species was detected in solution by C-13 NMR, and no solid compounds separated out under our experimental conditions. Finally, the relative amount of HCO3-, CO32-, and NH2CO2- in solution have been correlated to the molar ratio between free ammonia in solution and absorbed CO2.